This Tuesday, SpaceX’s Falcon 9 launched 22 Starlink satellites into low-Earth orbit (LEO), one of many satellites launches by the company. These satellites help bring internet services to people around the globe, but they also come with a risk.
According to a Federal Aviation Administration report issued last month, “if the expected large constellation growth is realized and debris from Starlink satellites survive reentry,” one person on the planet is expected to be injured or killed by debris every two years by 2035. At that point, an estimated 28,000 hazardous fragments are expected to survive reentries to Earth.
Overall, 85% of the expected risk to people on the ground and aviation from reentering debris in 2035 is due to Starlink launches, which are a main feature of billionaire Elon Musk’s SpaceX company.
“Starlink is a constellation of thousands of satellites,” orbiting closer to Earth than others, per the SpaceX website. Since they are closer to Earth, they can help provide internet access that supports streaming, online gaming, video calls and more.
A rapid increase in the use of non-geostationary satellite orbits, including medium and low-Earth orbits “represents an important innovation in satellite technology – and a potential breakthrough in connecting the unconnected so that they, too, can reap the benefits of today's digital economy,” said the International Telecommunications Union, a specialized branch of the United Nations.
In 2020, Congress enacted the Consolidated Appropriations Act of 2021, which included a request for an assessment of how the FAA’s launch and reentry licensing process may be leveraged to address the risk from reentering space debris. The FAA’s recent report was created in response.
“The dramatic rise of non-geostationary satellites, particularly those in low Earth orbit (LEO), poses an increased risk to people on Earth and aviation due to reentering debris,” said the report. It said that a stack of 60 Starlink first generation satellites has a mass of just over 17 tons and that the upper stage that placed those satellites in orbit has a mass of over 25 tons.
While FAA regulation is focused on the U.S., around a dozen countries have the ability to launch objects into space. Each country is expected to be responsible for monitoring these objects.
One example of potentially dangerous debris from another nation is the Chinese rocket body that reentered the Earth through random atmospheric reentry in May 2021. It launched April 29 of that year from the Wenchang Space Launch Center in the Hainan province. Debris from the rocket landed near the Maldives and no injuries were reported.
“The reentry was covered widely by U.S. and international media and received even wider criticism as an irresponsible space disposal,” said the FAA report.
Still, despite guidelines for purposeful reentry, large space objects reenter the Earth’s atmosphere about once a week, according to the FAA. Some of these objects were launched before disposal strategies were agreed upon.
“Given that seventy percent of the Earth is covered with water, most random reentries occur over water,” said the FAA. “However unlikely, large objects still can reenter over populated areas and may cause injury or casualty to people on the ground.”
It also said that “it has become abundantly clear that simply abandoning space objects in orbit is detrimental to the current and future use of space for the United States as well as for all spacefaring nations.”
This means that, as more satellites are launched into space, it is imperative to clear out objects from older launches in order to prevent collisions or re-entry. Collision warnings for objects passing close to each other in space increased from 210 in a single week in 2014 to 60,000 per week in August 2021.
In addition to collision risks and falling debris, the report noted that contamination and toxic chemical releases could pose a risk for Earth. However, it said “those instances are very rare and are best handled on a case-by-case basis.”
At this point, it is difficult to accurately predict when and where space objects will land back on Earth. In its report, the FAA listed recommendations to help leverage its licensing process to mitigate risks of space object reentry. On Sept. 20, the agency also proposed a rule to reduce the growth of space debris from commercial space ventures.